It says countries in Europe, Japan and the USA are using or testing the treatment for types of cancer, including spinal cord tumours and cancers of the prostate, lung, liver and brain, as well as some children's cancers.

Mr King said the family was not "neglecting" the boy and Ashya was "responding so much better" than he did in hospital.

What is proton beam therapy?

It uses charged particles instead of X-rays to deliver radiotherapy for cancer patients

The treatment allows high energy protons to be targeted directly at a tumour, reducing the dose to surrounding tissues and organs

In general, it gives fewer side-effects compared to high energy X-ray treatments

It can be used to treat spinal cord tumours, sarcomas near the spine or brain, prostate cancer, lung cancer, liver cancer and some children's cancers

In December 2011, the UK Department of Health said that proton therapy will be made available for patients in London and Manchester from 2018

BBC links

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